(i) Field of the Invention
The present invention relates to a novel vaccine formulation comprising at least one antigen, in particular an antigen of viral, bacterial or parasitic origin, and the method for its preparation.
Currently, the customary vaccines have a storage life which does not exceed 18 to 24 months at +4° C., whether they are oil-based or aqueous. Trials carried out by the Institute for Animal Health (IAH) in Great Britain have shown that oil-based vaccines frozen at −20° C. and at −70° C. lost their activity. Accordingly, commercial vaccines are labeled in this country with the label: “not to be frozen.”
Antigens may be stored for longer periods, up to 15 years, at very low temperature, in the form of concentrates. It is essential, in this case, to have means for formulating vaccines close to their storage site in order to avoid loss of time when the vaccine is urgently required.
These considerations have led the applicant to support work aimed at developing vaccines which can be stored for several years, and which are ready to use after thawing.